Heretofore, thermal generators have been greatly limited in their voltage production because of the construction of the thermocouples, said construction employing the use of solid metal wires, tapes, bars and the like.
The device of the present invention incorporates the use of two dissimilar powdered metals which are individually mixed with a suitable binder or flux which is printed on a suitable substrate having high thermal and electrical insulating properties.
It is the intent and scope of the present invention to directly convert the heat energy resulting from solar radiation as well as other forms of heat energy into electrical energy without moving parts, and in a manner that is neither energy or material intensive, by utilizing the Seebeck effect. One of the requirements to the production of thermoelectricity is that the temperature of one of the two junctions of each thermocouple must be elevated relative to the other. The greater the temperature differential, the greater the voltage potential between the two junctions. These voltages are very small. For example a chromel-constanton couple with a 100 degree centigrade temperature differential 0 degrees to 100 degrees C., the voltage would be 6.317 milivolts. Therefore a thousand such junctions, electrically in series, will produce 6.137 volts.
It is therefore apparent that in order to make a substantial use of thermoelectricity we must have two specifics: one, a great number of junctions and, second the greatest possible temperature differential. The manner in which thermocouples are currently produced is by fusing two different metals together in a metal wire, ribbon or bar form. The high temperature fusion is a weld where the two surfaces are melted together so that there is an intermixing of the metals at their junction surfaces.
One of the most significant differences in the approach of the instant invention concerns the manner by which the thermocouples are formed. Instead of starting with solid metals such as wire, flattened wire, ribbon or bars, powdered metals, very finely divided and mixed with a proper binder or flux to form a metallic ink, are used to print a multiplicity of thermocouples in series on a suitable substrate. This printing may be done via a silk screen method or by offset, lithographic or letterpress printing processes. The couples will be printed in a sequential manner, a copper, for example may go on first and then a constatan will go over the copper. They are then passed through an induction furnace where the metals are melted, due to the heat produced within the metal particles themselves. A microwave oven or a lazer controlled fuser may be employed instead of the induction furnace. An electrical path with solid metal is therefore guaranteed. Good couples are also guaranteed by an intermingling of the metals at said couples.
Therefore, one of the principal objects of the present invention is to provide a thermoelectric generator device utilizing a multiplicity of thermocouples defined in series on a narrow tape which may be rolled in a reel form or disposed in great numbers in an electrically interconnected strip form to define a generally rectangular panel.
A further principal object of the invention is to provide the two different metals in a fine powder form for mixture with an appropriate binder or flux to form a metallic ink for use with any of a variety of conventional printing processes for application to a suitable substrate.
Another object of the invention is to provide a means to enhance the temperature differential between the hot and cold sides of the thermocouples of alternating strips by providing an electrical connection between the bottom or cold side of a first of every pair of thermocouple strips to the top or hot side of a second strip thereof.
Yet another object of the present invention is to provide a method of producing the thermoelectric generator of the present invention comprising the steps of feeding an appropriate substrate, in sheet form of a predetermined length and width, sequentially through first and second metallic ink printers to define a plurality of lines of thermocouples along the length of each sheet; passing each sheet through a melter, such as an induction furnace, to melt the powdered metal particles into a solid mass with an intermingling of particles at each couple; passing each sheet through a slitter to slit each sheet into a plurality of ribbon strips with one line of thermocouples along the length of each strip; passing each plurality of ribbon strips into a bundler to define a bundle thereof, passng the bundles to an assembly station for assembly into a panel form, and passing the panels to a final collection station.
A further object of the invention is to provide a sheeting station between the melting station and the slitter when a continuous roll of substrate is passed through the first and second printers, and the melter.